N-Functionalized organolithium compounds via tellurium/lithium exchange reaction

Abstract

Um conjunto de amino teluretos foram preparados e testados em reações de troca telúrio/ lítio. Os compostos de organolítio contendo nitrogênio foram facilmente preparados utilizando N-Bz teluroaminas e uma combinação de n-butillítio/naftaleto de lítio nas reações de troca. Os correspondentes intermediários dilitiados foram capturados com vários eletrófilos, levando à formação dos respectivos produtos em bons rendimentos. A reação foi empregada na síntese de fenetilaminas.A set of tellurium amines have been evaluated in the tellurium/lithium exchange reaction. The nitrogen-containing organolithium compounds were efficiently prepared by using N-Bz tellurium amines and a mixture of n-butyllithium and lithium naphthalenide (LiNp) for performing the exchange reaction. The corresponding dianion intermediates were trapped with a wide range of electrophiles, furnishing the corresponding products in good to excellent yields. The reaction was also employed in the synthesis of phenethylamines.Keywords: tellurium/lithium exchange reaction, functionalized organolithium, dianion intermediate, phenethylamines IntroductionOrganolithium compounds are versatile and useful organometallics due to their excellent nucleophilic reactivity and importance in synthetic organic chemistry. 1 Among them, functionalized organolithium compounds represent an important class of intermediates with the ability of transfering the functionality to an electrophilic reagent. In this way, the preparation of functionalized organolithium compounds via halogen/lithium 2 and tin/ lithium 3 exchange reactions represent an interesting protocol of carbon-carbon bond formation for the synthesis of polyfunctionalized molecules, as well as a wide range of natural products. For years, several groups have been interested in the study and preparation of different α-, β-, γ-, δ-oxygen or nitrogen-functionalized organolithium intermediates and their reaction with electrophiles. 4,5 However, among these intermediates, the corresponding β-functionalized compounds, showed to be very unstable species, decomposing via β-elimination to give olefins. 6 On the other hand, organotellurium chemistry is a very broad and exciting field with many opportunities for research and development of applications in organic synthesis.7 Many different classes of organotellurium compounds have been prepared to date and successfully employed in different synthetic applications, 8 as well as in the total synthesis of natural products. 9 Among the several applications of organotellurium compounds, the formation of organolithium compounds via tellurium/ lithium exchange reaction represents an interesting protocol with a number of advantages over alternative methods. 10,11 Our research group has been working in the preparation and application of hydroxy alkyl tellurides in the tellurium/ lithium exchange reaction. 12 These compounds have been efficiently used as alternative organometallic sources of 1,4-dianion intermediates in the synthesis of diols, 13 spiroketals, 14 bioactive butenolides, 1...

Synthetic Organotellurium Compounds Sensitize Drug-Resistant Candida albicans Clinical Isolates to Fluconazole

“…The organotelluride compounds (Fig. 1) were synthesized as previously described (38)(39)(40)(41). All compounds were stored in a desiccator at 4°C, and stock solutions were prepared in DMSO.…”

Reactive organometallics from organotellurides: application in organic synthesis

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Antibacterial Compounds from Glycosmis puberula Twigs

“…The known compounds ( Figure 1) were characterized as arborinine (2) [12], citracridone I (3) [13], noracronycine (4) [14], Nmethylseverifoline (5) [15], dictamine (6) [16], robustine (7) [17], kokusaginine (8) [18], N- [2-(4-methoxyphenyl)ethylbenzamide] (9) [19], demethylsuberusin (10) [20] and bergapten 11 General: Melting points were determined on a Buchi B-540 visual thermometer. UV-vis spectra were recorded with a Perkin-Elmer UV-vis spectrometer.…”